The present invention relates to casings, in particular exhaust casings, forming parts of gas turbine aeroengines, and in particular parts of turboprops or turbojets.
In a gas turbine aeroengine, the exhaust casing performs several functions. It performs a structural function by receiving a rear suspension enabling the engine to be fastened to the fuselage of the aircraft. It also performs an aerodynamic function by serving to guide the primary stream coming from the engine. Finally, it also performs a function of passing services so as to enable the various components of the engine to be fed with air and oil.
It is common practice for an exhaust casing to be made up of an inner shroud mounted around a bearing support, an outer shroud of diameter greater than the inner shroud and arranged coaxially around it, and a plurality of casing arms that extend radially between the shrouds and that are fastened thereto at their radial ends.
The outer shroud is for receiving the rear suspension via clevis-type fittings. The casing arms connecting the shrouds together serve in particular to guide the primary stream coming from the engine. Furthermore, some of the casing arms are hollow in order to pass ducts for conveying air and oil to components of the engine.
The exhaust casing of a gas turbine engine presents the main drawback of being a part that is relatively heavy, since it is made of metal, which is particularly penalizing in terms of the fuel consumption of the aircraft.